Various dust filtration devices for filtering air-born particles heretofore have been designed and manufactured whether used in portable dust filtration machines, filtration assemblies for ceiling fans or as filtering assemblies used in connection with the fan and a window.
Such filtering devices are important to prevent the recirculation of dust laden particles.
For example, U.S. Pat. No. 4,715,872 discloses a portable dust collector having a rigid body which is particularly adapted for collecting wood dust and wood chips. Said portable dust collector comprises a housing having an outer side wall, a substantially open top, a substantially open bottom, and a dust-proof chamber within an interior thereof: a motor enclosed within said chamber; blower means driven by said motor for drawing air into said housing, said blower means being enclosed with said interior and having an inlet extending through said housing and communicating with an exterior thereof, and an outlet discharging within said housing; said chamber and blower means being shaped to form a passageway within said chamber between said open top and bottom; filter bag means attached to and enclosing said top for retaining particulates discharged into said interior by said blower while allowing air to pass therethrough; collection bag means attached to and enclosing said bottom for collecting particulates retained in said interior of said housing, whereby particulate-laden discharged from said outlet circulates in the vicinity of said collection bag means and also flows through said passageway to said filter bag means; and support means to an extending downwardly from said housing side wall for providing clearance below said housing sufficient for said collection bag.
U.S. Pat. No. 4,581,050 discloses a dust collector having a rigid body that is adapted to filter both fine and coarse air-born particles. Said dust collector includes two tubes which communicate through an interconnecting conduit. A first tube operates a cyclone which separates a great fraction of the dust or solid components from the incoming air and collects the same in a bag at the bottom of the tube. The second tube includes a filter unit composed of a coarser filter as well as a surrounding fine filter, the filter unit receiving the pre-purified air from the cyclone tube through the interconnecting conduit and separating the remaining dust particles therefrom.
U.S. Pat. No. 4,336,040 discloses a dust separator having a rigid housing which comprises a fan with a drive motor; cyclone separator, which is connected to the suction side of the fan and is arranged as a coarse separator and provided with an inlet for gaseous fluid mixed with dust; filter which projects freely coaxially into the cyclone apparatus and is arranged as a fine separator between the interior of the cyclone apparatus and the suction side of the fan; and outlet for cleaned gaseous fluid at the pressure side of the fan.
U.S. Pat. No. 5,094,676 utilizes a conventional ceiling fan to pull air downwardly through a filter medium. The fan and filter assembly comprising said invention has a motor and an upstanding tubular member above the motor which carries electrical wires to the motor. A collar concentrically positioned on the tubular member includes radially extending support members, each of which supports a radially extending horizontal arm. At the end of each such arm is attached, a vertically extending support member. A shallow cylindrical shroud is carried on the vertically extending support members, with the shroud extending a limited distance above the radially extending arms. A plurality of trays having porous bottoms are supported on the arms and contain a filter medium including a layer of activate charcoal granules covered by a membrane of polyester filaments.
U.S. Pat. No. 4,750,863 also discloses a filter device for use in conjunction with a ceiling fan for removal of smoke and other pollutants from the room during the operation of the fan. Said invention comprises a filter media frame comprising two interconnectable open topped halves having means adapted to fit abuttingly around the tubular conduit of a ceiling an, said frame having means thereon for retaining a filter.
It is an object of this invention to provide an improved filter for a fan.
One aspect of this invention resides in a filter for a fan comprising an air permeable material exteriorally bracing the suction portion of the fan.
It is another aspect of this invention to provide a filter for a circulating fan having a safety cage and a stand connected to the suction portion of the fan comprising: a web of air permeable material presenting two opposite ends connected to one another so as to define a first and second opening; elastic means associated with each said first and second opening; whereby said air permeable material and said first and second opening are adapted to stretch over said fan, with said first opening elastically embracing said suction portion of said fan adjacent said stand and said other opening elastically embracing said safety cage of said fan.